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So what do I need to know about adding Solar to an RV

That's sort of confusing that the PWM controller can accept 55v but charge at 12v....

I was under the impression that the voltages have to be standard ranges in/out.
An example would be panels at 24v and batteries at 24v or panels at 36v and batteries at 36v
not 46v panels charging 12v batts. That is what MPPT is for.
I am not saying I am right just what I thought was right.
More reading maybe?:homer:
 
The tech sheet says it can do it, but I see what you mean. It must transform the PV voltage to the "auto detected' battery voltage automatically, just in a slightly less efficient way than the MPPT versions:


1628706275165.png
 
GLTHFJ60 said:
The tech sheet says it can do it, but I see what you mean. It must transform the PV voltage to the "auto detected' battery voltage automatically, just in a slightly less efficient way than the MPPT versions:

Click to expand...
I downloaded the manual too to try and get some clarification but saw what you saw.
It's cheap enough if the smoke goes no harm to the pocket book but you might want to verify with them before attempting it.
 
Renogy who I believe is the same as HQST has the same solar charge controller with added detail in there literature.

1628708088052.png
 
Yeah, the input voltage range is the same, but the total array wattage is limited depending if you're charging a 12v vs a 24v battery. Makes sense, as the transformer has to "work harder" to make up the voltage differential with high input voltage and low charging voltage.

Cool shit.
 
GLTHFJ60 said:
Yeah, the input voltage range is the same, but the total array wattage is limited depending if you're charging a 12v vs a 24v battery. Makes sense, as the transformer has to "work harder" to make up the voltage differential with high input voltage and low charging voltage.

Cool shit.
Click to expand...
Not sure if we are on the same page but the PV limit charging 12v is 25v not the 55v number the HQST has listed.
 
CarterKraft said:
Not sure if we are on the same page but the PV limit charging 12v is 25v not the 55v number the HQST has listed.
Click to expand...

Oh, I see now, you were referring to the renogy manual. That's not what HQST states in their manual, so perhaps there is a difference between renogy and HQST.
 
GLTHFJ60 said:
Oh, I see now, you were referring to the renogy manual. That's not what HQST states in their manual, so perhaps there is a difference between renogy and HQST.
Click to expand...
I am not sure, if you are concerned with wasting some money you might inquire before sending adding panels.
 
CarterKraft said:
Not sure if we are on the same page but the PV limit charging 12v is 25v not the 55v number the HQST has listed.
Click to expand...
looking at the renogy manual, i'm inclined to agree with what you are surmising; in order to use that controller to the MAX with 600W total panels, it would need to be hooked up to 24v worth of batteries.

same price point, same design, so i'd imagine the same specs hold true. If i'm sticking with 12v worth of batteries, then i'll just stick with 300W total panels all in parrallellel. ( I honestly think 100w panel will meet my needs)

but for $20, if it does go up in smoke i'm not too worried about it :laughing: doing some reading, the biggest reason the PWM is much cheaper than the MMPT is more or less the ~20% drop in efficiency for rv sized systems. with the occasional use that i've got, i'm happy to have some efficiency drop.
 
Provience said:
looking at the renogy manual, i'm inclined to agree with what you are surmising; in order to use that controller to the MAX with 600W total panels, it would need to be hooked up to 24v worth of batteries.

same price point, same design, so i'd imagine the same specs hold true. If i'm sticking with 12v worth of batteries, then i'll just stick with 300W total panels all in parrallellel. ( I honestly think 100w panel will meet my needs)

but for $20, if it does go up in smoke i'm not too worried about it :laughing: doing some reading, the biggest reason the PWM is much cheaper than the MMPT is more or less the ~20% drop in efficiency for rv sized systems. with the occasional use that i've got, i'm happy to have some efficiency drop.
Click to expand...
For a small budget system the price point is perfect, I can't argue that.
I have a $7 PWM controller on a customers sign lighting. It's pretty amazing what you can do for $7.
 
It's effin stupid really, a throw away flashlight costs more n that!:grinpimp:
i'm hoping to squeeze out a tad more outta the 2 100w panels and 2 gp 30 12 v batteries by swapping in an mppt ...
 
picked up a new coach battery

Duracell Ultra BCI Group 31M 12V 650CCA Flooded Marine & RV Battery - SLI31MDC at Batteries Plus Bulbs

Group 31 12 volt replacement deep cycle battery for marine, boat and RV use. Stay out on the water longer with this powerful 105 amp hour deep cycle battery!
www.batteriesplus.com www.batteriesplus.com

12v 105 AH group 31.

old one was probably a group 27 and over 10 years old, it had gone from fully charged down to 6 volts in about 2 months of sitting with everything off.

The single 100w panel supposedly will average 30-40 AH over a good day, the battery should be happy at 50 AH run down time. I can't imagine the 'fridge is sucking up 5 amps to run cruising at night, so this should work out.

in addition to the battery not being great, the battery box was also in rough shape.

IMG_2021-08-11_14-46-51.jpeg


but hey, at least it didn't completely destroy the coach side of things :laughing:
IMG_2021-08-11_14-47-20.jpeg


so i cut off the little mount feet that were there and wire brushed off some gunk. made a simple frame from 1x1x1/8" angle

IMG_2021-08-11_16-44-14.jpeg


after a bit of pondering and looking at stuff, ended up deciding to go with a tray rather than a full on box. 40 or 60 thou aluminum seemed easy enough. Folded up 2 edges and managed to screw up rolling a couple beads, good practice if nothing else

IMG_2021-08-11_16-44-20.jpeg


swore up and down that I wasn't going to use self tapping screws every again, that was a lie. screwed it together, broke 1 drill bit and 1 screw and managed to cut myself :rasta:
IMG_2021-08-11_17-15-27.jpeg


and after considering all the options, decided an old harbor freight strap would be the hot ticket. the tray retains the battery east/west and the frame will ultimately keep it from sliding out north/south so the strap shouldn't have too much work to do
IMG_2021-08-11_17-35-42.jpeg


and this kind of gives me a better idea of what kind of space there is to work with if it turns out 2 batteries are needed.
 
adding this note in

  • Max. PV Input Power: 450W (12V), 900W (24V)
Click to expand...

hqsolarpower.com

30 Amp 12V/24V PWM Common Positive Solar Charge Controller with LCD Display and 5V 1A USB Port

This controller is an intelligent and multifunctional solar charger controller.
hqsolarpower.com hqsolarpower.com

this is from the specifications for the 30 amp PWM controller from HQST, same but larger version of what i've got. without a doubt, that confirms the above information. 20 amp PWM is good for max 300W system charging 12v battery bank.

that makes life a little easier
 
alright, wanted to give an update to this thread with some results. Fan-fucking-tastic in all honesty. We just did 8 days parked, with some noticeable smoke in the sky for most of those and 1 day when it was thick enough there was hardly a shadow all day. The single 100W panel was plenty to keep up with our use :smokin: with $4/gallon gas, it probably saved me $50 not running the gen just this week so that should be a reasonably quick payback (~4weeks camping in total). more than that though, it was just easy.

every morning i'd wake up and check the battery either right before or right at sunrise, it was always 12.5 or 12.6v. meaning during the day it was building plenty of juice to top off the battery.

did it matter that that it was free-range rather than mounted flat to the roof? I think so. I was able to get 4+ amps worth of charging out of it for a few hours even through the haze just approximating the angle to my latitude (check at noon and 1pm for the smallest possible shadow) and setting that angle leaned against the bumper.

granted, i'm not a big user of power. running a 1 or two lights for a few hours at night, occasional fan use, running the monitors for the fridge/propane and such, running the water pump as much as needed, and seemed like near constant phone charging between 4 people. no TV or microwave use.

knowing now that i'm able to keep up and really not dip much into the battery, i'm going to get a inverter so that i can charge my computer and run the tiny air mattress pump off the coach battery rather than using the wifes car.

for being cheap, easy and fairly quick it worked damned well and i'm impressed.
20210829_144436.jpg
 
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Glad it worked out for you.

The "easy" part for me makes all the difference.
My 400w roof mount solar, 2x GC2 batteries and inverter really seems like perpetual power in the summer months.
 
CarterKraft said:
Glad it worked out for you.

The "easy" part for me makes all the difference.
My 400w roof mount solar, 2x GC2 batteries and inverter really seems like perpetual power in the summer months.
Click to expand...
I really appreciate all the help from this thread, yall got me to make the jump and it was way less scary in reality :laughing:
 
CarterKraft said:
Glad it worked out for you.

The "easy" part for me makes all the difference.
My 400w roof mount solar, 2x GC2 batteries and inverter really seems like perpetual power in the summer months.
Click to expand...

Yeah summer is easy, winter gets harder :lmao: I still don't have enough solar to run an AC unit sadly.
 
Java230 said:
Yeah summer is easy, winter gets harder :lmao: I still don't have enough solar to run an AC unit sadly.
Click to expand...
Agreed, if I did much winter dry camping I would double or triple my panel wattage, not exceed rated panel voltage but greatly exceed the amperage.
The Micro-Air soft starts are pretty amazing for AC units, I saw someone use one on a household AC unit @ 240v and it seems to be a huge improvement in start current.

After putting the inverter AC wall unit in my shop this summer there is a huge advantage to that type of power drive system.
 
alright, this is semi-related to the thread so i'm putting it here :rasta:


also uploaded as an attachment in case and when the website changes so that hopefully the information doesn't get dead linked later

this link to a set of inverter instructions has a really good explanation of the battery side of things

my coach is setup in typical fashion, so i'm looking at getting a ~300w or so inverter to put some more stress on my battery. Being able to operate the many various 120v things that are more readily available than their 12v counterparts without running the generator, while letting the solar take all day or even a couple days to refill the battery is appealing :laughing:

www.toboaenergy.com

Samlex America PST-300-12 Pure Sine Wave Inverter 300W

Samlex America PST-300-12 Pure Sine Wave Inverter 300W DC-AC inverter converts 12 Volts DC to 300 Watts of pure sine-wave AC power at 120 Volts, 60 Hz
www.toboaenergy.com

samlex seems to be in either the high-end chinese products or the low end domestic, they claim to have manufacturing in USA, China, Netherlands, Taiwan and Canada...tough gamble, but makes me feel better than something half the price straight off the boat. yeah, yeah, the rest of the stuff i've bought was china special :laughing:
 

Attachments

  • 11001-PST-300-12-24-1215_Web_ToboaEnergyResourcesLLC.pdf
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Provience said:
alright, this is semi-related to the thread so i'm putting it here :rasta:


also uploaded as an attachment in case and when the website changes so that hopefully the information doesn't get dead linked later

this link to a set of inverter instructions has a really good explanation of the battery side of things

my coach is setup in typical fashion, so i'm looking at getting a ~300w or so inverter to put some more stress on my battery. Being able to operate the many various 120v things that are more readily available than their 12v counterparts without running the generator, while letting the solar take all day or even a couple days to refill the battery is appealing :laughing:

www.toboaenergy.com

Samlex America PST-300-12 Pure Sine Wave Inverter 300W

Samlex America PST-300-12 Pure Sine Wave Inverter 300W DC-AC inverter converts 12 Volts DC to 300 Watts of pure sine-wave AC power at 120 Volts, 60 Hz
www.toboaenergy.com

samlex seems to be in either the high-end chinese products or the low end domestic, they claim to have manufacturing in USA, China, Netherlands, Taiwan and Canada...tough gamble, but makes me feel better than something half the price straight off the boat. yeah, yeah, the rest of the stuff i've bought was china special :laughing:
Click to expand...
What are you trying to achieve? 300w is nearly nothing. If your going to the trouble of adding an inverter, get an inverter charger.

Also at $175 I am 99% sure it wont be pure sine wave. Weather that really matters or not is up to you.

FWIW I would go 1500W or bigger....
 
Java230 said:
What are you trying to achieve? 300w is nearly nothing. If your going to the trouble of adding an inverter, get an inverter charger.

Also at $175 I am 99% sure it wont be pure sine wave. Weather that really matters or not is up to you.

FWIW I would go 1500W or bigger....
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i'll be sad if it isn't pure sign wave :laughing: seems like the modified were all under $100. not looking for a bunch of use, mostly charging other battery powered stuff and using normal receptacles. I've only got a single battery, my concern with a 1500w inverter was that it would drain the battery pretty dang quick if i ran anything 1k watts or so.

after a bit more reading i went ahead and bought it from invertersRus.com :homer:
 
Provience said:
i'll be sad if it isn't pure sign wave :laughing: seems like the modified were all under $100. not looking for a bunch of use, mostly charging other battery powered stuff and using normal receptacles. I've only got a single battery, my concern with a 1500w inverter was that it would drain the battery pretty dang quick if i ran anything 1k watts or so.

after a bit more reading i went ahead and bought it from invertersRus.com :homer:
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Yeah mine eats amps fast if you do big stuff. Microwave is 85 ish amps!

Doesn't you converter make enough power to charge little stuff?
 
Java230 said:
Yeah mine eats amps fast if you do big stuff. Microwave is 85 ish amps!

Doesn't you converter make enough power to charge little stuff?
Click to expand...

well, this is where I'm probably all messed up.

As far as I understand the coach wiring stuff, lights, pumps, fans, TV outlet (not in use) are all wired to run off the coach battery and are 12v systems

refrigerator cooling (when not propane), microwave, air conditioner, house style wall outlets all only run off shore power or generator power.

Shore power and generator also charge the coach battery from a converter, engine alternator charges the coach battery directly...or magic.

the solar charge controller has a 0.5 amp usb on it, that i can't access because that's pretty low power

I don't believe that any of the existing wall outlets are setup to run off the coach battery alone.

the computer uses a 90w charger, nintendo and a small 120v TV combine for <100w, little 120v air pump is ~180w, battery vacuum has a 120v style charger. it's just easier to find stuff for 120 style outlets :laughing:

this would be faster and easier to use the "high speed" chargers for the phones as well rather than the cheap lighter adapter style
 
Provience said:
i'll be sad if it isn't pure sign wave :laughing: seems like the modified were all under $100. not looking for a bunch of use, mostly charging other battery powered stuff and using normal receptacles. I've only got a single battery, my concern with a 1500w inverter was that it would drain the battery pretty dang quick if i ran anything 1k watts or so.

after a bit more reading i went ahead and bought it from invertersRus.com :homer:
Click to expand...
Samlex brand is fine I have a similar 1500 watt inverter in my RV. And I think the magic of the inverter is to charge directly from the however many watts of solar you have to whatever the device is. With my two GC2 golf cart batteries I can easily run all night watching TV, the kids leave their TV on the furnace runs on and off and I still am not over 50% discharge the next morning.

That works great because I have plenty of sun to recharge if there wasn't any sun I'd be in trouble after one day of doing that.
Keep that in mind when you are laying out these systems and intended uses.

Just keep in mind with a single battery and 100w of charging you will be pretty hamstrung to low watt charging, and idle current of the inverter and wall warts etc. Will suck some power even when you don't actively use it.
 
CarterKraft said:
Samlex brand is fine I have a similar 1500 watt inverter in my RV. And I think the magic of the inverter is to charge directly from the however many watts of solar you have to whatever the device is. With my two GC2 golf cart batteries I can easily run all night watching TV, the kids leave their TV on the furnace runs on and off and I still am not over 50% discharge the next morning.

That works great because I have plenty of sun to recharge if there wasn't any sun I'd be in trouble after one day of doing that.
Keep that in mind when you are laying out these systems and intended uses.

Just keep in mind with a single battery and 100w of charging you will be pretty hamstrung to low watt charging, and idle current of the inverter and wall warts etc. Will suck some power even when you don't actively use it.
Click to expand...
i'm planning on exclusively using it with alligator style clips directly off the battery, which is mounted conviniently in the middle of the "hallway" rather than permanent mounting, so that it won't get "let on" or hopefully even plugged in longer than needed.
 
Provience said:
well, this is where I'm probably all messed up.

As far as I understand the coach wiring stuff, lights, pumps, fans, TV outlet (not in use) are all wired to run off the coach battery and are 12v systems

refrigerator cooling (when not propane), microwave, air conditioner, house style wall outlets all only run off shore power or generator power.

Shore power and generator also charge the coach battery from a converter, engine alternator charges the coach battery directly...or magic.

the solar charge controller has a 0.5 amp usb on it, that i can't access because that's pretty low power

I don't believe that any of the existing wall outlets are setup to run off the coach battery alone.

the computer uses a 90w charger, nintendo and a small 120v TV combine for <100w, little 120v air pump is ~180w, battery vacuum has a 120v style charger. it's just easier to find stuff for 120 style outlets :laughing:

this would be faster and easier to use the "high speed" chargers for the phones as well rather than the cheap lighter adapter style
Click to expand...
You may be right, I have not had a standard "converter" in a long time :lmao:

Sounds like that should be good for your uses. I have a 3kw on mine, way overkill, but the packaging was a better fit than the 1500w/2k
 
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